Designing for Privacy

Building for Privacy – Fences and Pergolas

It’s one of those subjects that rarely comes up until you nail the first few boards to your Fence or your Pergola.  In the case of the Pergola, you may also wish to consider how much light you let in through the rails along the top.

In the case of a Fence, it’s really just a matter of deciding what style of fence you’d like, and how much privacy can be built into that style.  If you’re building a short safety fence around a deck with rod iron poles, don’t expect to get too much privacy.  Whereas if you’re building a simple 2 rail fence with tight fence boards, you can achieve total privacy.  Again, consider your application and how much privacy you’d like before you buy materials.

To get us thinking about privacy when building fences, I broke out the old pencil and paper and threw together this quick diagram so we can all talk about the same things.  Here’s a simple two rail fence that most are familiar with: (please no comments on the quality of my drawing skills :)

Fence Example

Example Privacy Fence with Slots

OK, from the diagram above, we have two Fence posts with a distance ‘R’ between them, which represents the length of each of our Fence rails.  We also have ‘n’ Fence boards that are each, ‘w’ inches wide.  So in the case where we were using 1×6 Fence boards, maybe our ‘w’ would be 5½ inches, remember, when speaking of Dimensional Lumber, a 1×6 is about 5½ inches wide.

To calculate what the ideal spacing should be, we need to first consider whether we’ll start with fence boards placed up against the posts, or will we start with a space up against the post?  Its really just a matter of style and preference, but depending on which option you choose, you’ll calculate the spacing a little differently.  In the case where we’ll start with no space, and a Fence board goes right up against the post, we’ll be leaving n-1 spaces as we add pieces across the Fence rail, so the spacing in between each Fence board would be calculated as:

(R – (w * n)) ÷ (n – 1)

and in the case where we start with spaces on either side of each post, we’ll be adding two more spaces to our rail, so our calculation changes to:

(R – (w * n)) ÷ (n + 1)

Here’s an example.  If we had Fence rails that were 5 feet long, then we’d have: R = 5 feet or 60 inches. If we wanted to put 8 1×6 Fence boards along those rails, starting with spaces on either side of our posts, our spacing would work out to be:

(60 – (5½ * 8)) ÷ (8 + 1) = 16 ÷ 9 = 1¾ inches between each 1×6  (approx.)

Which seems reasonable, or we could try fitting another 1×6 on to the rail to get:

(60 – (5½ * 9)) ÷ (9 + 1) = 1 inch between each 1×6 (approx.)

So we can see that by adding another 1×6 onto the rail, we tighten up the spacing in order to get that perfect fit for each space.  We also make the Fence much more private, and this is where a little experience and trial and error can come in handy.  Ideally, you know how many boards you’ll be laying out across the Fence rail before you make it to the store to buy supplies.

Here’s another thought. Rather than placing all the Fence boards on one side, you’ve probably seen Fence boards placed on alternate sides of the rail.  Here’s a top down view of what the Fence boards would look like in this sort of an arrangement with the alternating version on the top of the diagram:

Fence Slot Options

Options For Fence Slot Placement

This gives the Fence a nice look, but again, you’ll need to be thinking about privacy because the spacing options discussed above may not work out as well with this style of Fence.  In fact, you’ll realize that you need to overlap the Fence boards on one side with the Fence boards on the other side just to get a reasonable amount of privacy.  In these cases, the calculations for the spacing amounts is the same, but because the Fence has some space between the boards on each side, you’ll generally consume more boards for this style.

So there you have it, a few ideas for Fence construction, privacy, and how to go about laying out the Fence boards for the perfect fit.  If it sounds like a hassle, it can be, because often there’s no way to really know how private the results will be without experiencing it.  As you can see, from my pencil pictures, a drawing is of little help in this situation.  This is where a software planning application can help.

There’s two nice things 3D Build Planner can help with here.  The first is visualization.  It’s true that nothing can replace a real project and an inspection, but through the power of some first class graphics, 3D Build Planner can give you a pretty good idea of how private your Fence is going to be.  Secondly, all those calculations?  3D Build Planner makes life easier by taking care of all that for you.  3D Build Planner will suggest spacing options for you, and has tools to let you experiment with privacy options until you’re satisfied.  Something you just won’t find in hard coded plans, spreadsheet applications, or drawing packages.

Give the demo version a try here at or watch the online video that shows how the Joint Wizard can come to the rescue.

Happy Building,

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